Review on the validity and reliability of self-reported work-related illness

Each year HSE sponsor two surveys in the Labour Force Survey (LFS): (1) the ‘workplace injury’ module and (2) the ‘work-related illness’ module.

The ‘work-related illness’ module estimates the prevalence and incidence of work-related illness from the number of people who have conditions that they think have been caused or made worse by work (regardless of whether they have been seen by doctors). This module is usually referred to as self-reported work-related illness (SWI).

Self-report measures are potentially vulnerable to distortion due to a range of factors, including social desirability, dissimulation or response style. To extend knowledge on the reliability and validity of self-reported work-related illness HSE commissioned a review of the literature.

The main findings are reproduced below and include the conclusion that from the evidence, it is “not possible to come to a final judgment on the value of self-reported work-related illness”.

Conclusions – main findings

“Questionnaires and interviews are frequently used methods to assess self-reported work-related illness. Many self-report measures are not aimed at work or the work situation.

For epidemiological research, there is an extensive choice in valid and reliable self-report measures on musculoskeletal disorders and mental health problems, including a number of questionnaires designed for use in work situations.

In most studies, the reliability and validity of self-reported illness is assessed by comparison with a “gold standard” of an expert opinion based on clinical examination and/or on testing. Only a small minority of the studies explicitly included self-assessed work-relatedness of a health condition.

From the evidence, it is not possible to come to a final judgment on the value of self-reported work-related illness in general. The validity of measuring work-related illness by self-reports depends on the purpose for which it is used, the context in which it is used and the health condition that is measured.

The agreement on an individual level between the result of medical examination and self-report is low to moderate. Usually, there are a substantial number of false positives and false negatives in self-reported illness as well as self-reported work-relatedness.

On the group or population level, the agreement between the results of self-report measures and results coming from external sources can be better, especially when using self-diagnosed questionnaires and questionnaires that use a specific combination score of health symptoms.”